American Indian Diabetes Research Articles

Associations of processed meat and unprocessed red meat intake with incident diabetes: the Strong Heart Family Study

Fifty percent of American Indians (AIs) develop diabetes by age 55 y. Whether processed meat is associated with the risk of diabetes in AIs, a rural population with a high intake of processed meat (eg, canned meats in general, referred to as "spam") and a high rate of diabetes, is unknown. We examined the associations of usual intake of processed meat with incident diabetes in AIs. This prospective cohort study included AI participants from the Strong Heart Family Study who were free of diabetes and cardiovascular disease at baseline and who participated in a 5-y follow-up examination (n = 2001). Dietary intake was ascertained by using a Block food-frequency questionnaire at baseline. Incident diabetes was defined on the basis of 2003 American Diabetes Association criteria. Generalized estimating equations were used to examine the associations of dietary intake with incident diabetes. We identified 243 incident cases of diabetes. In a comparison of upper and lower quartiles, intake of processed meat was associated with a higher risk of incident diabetes (OR: 1.63; 95% CI: 1.21, 2.63), after adjustment for potential confounders. The relation was particularly strong for spam (OR for the comparison of upper and lower quartiles: 2.06; 95% CI: 1.30, 3.27). Intake of unprocessed red meat was not associated with incident diabetes (OR for the comparison of upper and lower quartiles: 0.90; 95% CI: 0.59, 1.37). The consumption of processed meat, such as spam, but not unprocessed red meat, was associated with higher risk of diabetes in AIs, a rural population at high risk of diabetes and with limited access to healthy foods.

Incidence rates and predictors of diabetes in those with prediabetes: the Strong Heart Study

The association between prediabetes as currently defined and incident diabetes in populations with widespread obesity, insulin resistance syndrome, and diabetes is not well defined. In this article, diabetes risk factors and incidence rates in American Indians (AI) with prediabetes are examined. A total of 1677 AI who were nondiabetic at baseline was examined during a median 7.8-year follow-up as part of the Strong Heart Study (SHS). Risk factors for incident diabetes were measured. Prediabetes was defined according to American Diabetes Association 2003 criteria as having impaired glucose tolerance (IGT) (2-h plasma glucose [2-h PG] >or= 140 mg/dL but < 200 mg/dL) and/or impaired fasting glucose (IFG) (fasting plasma glucose [FPG] >or= 100 mg/dL but < 126 mg/dL). Prediabetes was identified by FPG alone in 87.5%. Diabetes incidence in those with baseline prediabetes was 66.1/1000 person-years, with a hazard ratio (HR) of 2.35 (95% conference interval: 1.84-3.01), compared with participants with normal glucose tolerance (NGT) at baseline. Elevated A(1c), 2-h PG, and fasting insulin (FI); albuminuria; and obesity were significantly associated with conversion from prediabetes to diabetes. Younger age, elevated FI (or body mass index [BMI] in models without FI), and less physical activity were significantly associated with conversion from NGT. Prediabetes is an independent predictor of conversion to type 2 diabetes in AI, and most can be identified through a fasting glucose measure. Measures of obesity, A(1c), FPG, 2-h PG, FI, albuminuria, and insulin resistance (IR) help predict this conversion. Obesity is a modifiable risk factor. Strategies to reduce obesity should be emphasized in individuals with prediabetes.

Physical Activity and Incident Diabetes in American Indians: The Strong Heart Study

The authors examined the association between total physical activity (leisure-time plus occupational) and incident diabetes among 1,651 American Indians who participated in the Strong Heart Study, a longitudinal study of cardiovascular disease and its risk factors among 13 American Indian communities in 4 states (North Dakota, South Dakota, Oklahoma, and Arizona). Discrete Cox models were used to examine the association between physical activity level (in tertiles), compared with no physical activity, and incident diabetes, after adjustment for potential confounders. During 10 years of follow-up (f1989-1999), 454 incident cases of diabetes were identified. Compared with participants who reported no physical activity, those who reported any physical activity had a lower risk of diabetes: Odds ratios were 0.67 (95% confidence interval (CI): 0.46, 0.99), 0.67 (95% CI: 0.45, 0.99), and 0.67 (95% CI: 0.45, 0.99) for increasing tertile of physical activity, after adjustment for age, sex, study site, education, smoking, alcohol use, and family history of diabetes. Further adjustment for body mass index and other potential mediators attenuated the risk estimates. These data suggest that physical activity is associated with a lower risk of incident diabetes in American Indians. This study identifies physical activity as an important determinant of diabetes among American Indians and suggests the need for physical activity outreach programs that target inactive American Indians.

Diabetic nephropathy in American Indians, with a special emphasis on the pima Indians

Diabetes affects American Indians disproportionately compared with other racial/ethnic groups in the United States and is almost exclusively type 2 diabetes. Much of our knowledge about diabetes in American Indians comes from studies in a few tribes. The most extensively studied American Indians are the Pima Indians from the Gila River Indian Community in Arizona, who participated in a longitudinal study of diabetes and its complications between 1965 and 2007. They have one of the highest reported incidence and prevalence of type 2 diabetes in the world, and kidney disease attributable to diabetes is a major cause of morbidity and mortality. In this article, we examine the course, determinants, and trends of diabetic kidney disease in American Indians, with special emphasis on studies conducted in the Pima Indians. We also review therapeutic strategies for managing diabetic kidney disease.

SMOKING IN AMERICAN INDIAN AND ALASKA NATIVE PEOPLE WITH DIABETES REVISITED

Morton et al's article on smoking and diabetes in American Indians and Alaska Natives raises important concerns.1 Because of the longstanding organized emphasis on smoking ascertainment and cessation for individuals with diabetes, the findings likely reflect a serious ascertainment bias. The Indian Health Service (IHS) Division of Diabetes has measured smoking status in American Indians and Alaska Natives with diabetes since 1986 with the Annual Diabetes Care and Outcomes Audit.2 The IHS Standards of Care for Diabetes emphasize smoking assessment. In 2007, 91.8% of patients with diabetes, systemwide, were assessed for tobacco use. Less than a quarter (23.4%) reported current tobacco use. Of these, 31.6% were referred for cessation counseling. Epidemiologic studies of cardiovascular risk factors have not found increased smoking rates in American Indians and Alaska Natives with diabetes compared with those without diabetes. The Strong Heart Study, conducted in 13 American Indian communities in Arizona, Oklahoma, and the Dakotas, found wide variations in tobacco use by community.3 A special analysis requested for this letter showed that smoking rates in those with diabetes were significantly lower (27%) than in those without (41%; P < .001; Y. Zhang and E. Lee, personal communication, Strong Heart Study). The Inter-Tribal Heart Project in Minnesota also found lower rates of tobacco use in those with diabetes (53.1%) compared with participants without diabetes (68.9%; P < .05; N. Burrows and L. Geiss, personal communication, Centers for Disease Control and Prevention). The Centers for Disease Control and Prevention's Behavioral Risk Factor Surveillance System data from 2005 to 20064 showed no significant differences in current smoking prevalence between American Indian and Alaska Native adults with diabetes and those without (29.6% vs 32.2%, respectively; N. Burrows and L. Geiss, personal communication, Centers for Disease Control and Prevention). Data presented in the report are also subject to other limitations; notably, the case definition may have compromised the accuracy of case identification, and the duration of monitoring cases may have been affected by a differential risk of mortality. Because the authors ascertained diabetes from an electronic data set using only 1 diagnosis of diabetes during the 5-year period, they may have included in the data set persons who didn't have diabetes. Aside from some local IHS improvement activities, most studies recommend at least 2 visits be used to ascertain diabetes from administrative sources.5 Smoking poses a particular mortality risk for persons with diabetes. To the extent that the risk of premature death is higher for smokers with diabetes than for those without diabetes, smokers who survived to be included in the study may have included fewer persons with diabetes. Thus, before the distribution of currently limited IHS smoking cessation resources is modified, the evidence for redistributing those resources should be more substantial than that presented by Morton et al.1

A Search for Variants Associated With Young-Onset Type 2 Diabetes in American Indians in a 100K Genotyping Array

To identify genetic variants in linkage disequilibrium with those conferring diabetes susceptibility, a genome-wide association study for young-onset diabetes was conducted in an American-Indian population. Data come from 300 case subjects with type 2 diabetes with age of onset <25 years and 334 nondiabetic control subjects aged >or=45 years. To provide for tests of within-family association, 121 nondiabetic siblings of case subjects were included along with 140 diabetic siblings of control subjects (172 sibships). Individuals were genotyped on the Affymetrix 100K array, resulting in 80,044 usable single nucleotide polymorphisms (SNPs). SNPs were analyzed for within-family association and for general association in case and control subjects, and these tests were combined by Fisher's method, with priority given to the within-family test. There were more SNPs with low P values than expected theoretically under the global null hypothesis of no association, and 128 SNPs had evidence for association at P < 0.001. The association of these SNPs with diabetes was further investigated in 1,207 diabetic and 1,627 nondiabetic individuals from the population study who were not included in the genome-wide study. SNPs from 10 genomic regions showed evidence for replication at P < 0.05. These included SNPs on chromosome 3 near ZNF659, chromosome 11 near FANCF, chromosome 11 near ZBTB15, and chromosome 12 near SENP1. These studies suggest several regions where marker alleles are potentially in linkage disequilibrium with variants that confer susceptibility to young-onset type 2 diabetes in American Indians.

Is Psychological Distress a Risk Factor for the Incidence of Diabetes Among American Indians? The Strong Heart Study

This study was conducted to determine if psychological distress increases the risk of type2 diabetes in American Indians. A prospective cohort study of 919 individuals free of diabetes from 13 Native communities was conducted to determine who developed diabetes. Psychological distress was assessed at baseline (1993-1995) by the Mental Component Summary (MCS) of the Short Form-36. The risk of diabetes was estimated at follow-up (1997-1999) according to quartiles of the MCS score. There was no evidence of a trend between psychological distress and the development of diabetes (ptrend = .73). The risk of diabetes in individuals in the highest quartile (17.5%) was nearly identical to that in the lowest quartile (16.5%) (odds ratio = 1.1, 95% confidence interval 0.7-1.7). The absence of association persisted even after adjustment for known risk factors for diabetes. Thus the study concludes that psychological distress is not related to the incidence of diabetes in American Indians.

Associations of community-basedhealth education programs with food habits and cardiovascular disease risk factors among Native Americans with diabetes: The Inter-Tribal Heart Project, 1992 to 1994

Diabetes is a major health problem among most Native-American populations ( (1) Gohdes D. Kaufman S. Valway S. Diabetes in American Indians an overview. Diabetes Care. 1993; 16: 239-243 Crossref PubMed Scopus (51) Google Scholar , (2) Howard B.C. Lee E.T. Cowan L.D. Devereux R.B. Galloway J.M. Go O.T. Howard W.J. Rhoades E.R. Robbins D.C. Sievers M.L. Welty T.C. Rising tide of cardiovascular disease in American Indians. The Strong Heart Study. Circulation. 1999; 99: 2389-2395 Crossref PubMed Scopus (358) Google Scholar ) and is a significant risk factor for cardiovascular disease (CVD). The prevalence of non-insulin-dependent diabetes mellitus among Native Americans in North America has increased since the 1940s and is about 2.8 times higher than the overall US prevalence ( (3) Young TK. The Health of Native Americans. 1994; (London, England: Oxford University Press): 145-148 Google Scholar , (4) West K.M. Diabetes in American Indians and other native populations of the new world. Diabetes. 1974; 23: 841-855 Crossref PubMed Scopus (145) Google Scholar , (5) Will J.C. Strauss K.F. Mendlein J.M. Ballew C. White L.L. Peter D.G. Diabetes mellitus among Navajo Indians findings from the Navajo Health and Nutrition Survey. J Nutr. 1997; 127: 2106S-2113S PubMed Google Scholar , (6) Valway S. Freeman W. Kaufman S. Welty T. Helgerson S.D. Gohdes D. Prevalence of diagnosed diabetes among American Indian and Alaska Natives, 1987. Estimates from a national outpatient data base. Diabetes Care. 1993; 36: 271-276 Crossref Scopus (48) Google Scholar ). Among the tribes of the Great Lakes the estimated prevalence of diabetes is reported to be 15.2% ( (7) National Institutes of Diabetes and Digestive and Kidney Diseases, National Diabetes Information Clearinghouse. Diabetes in Native Americans and Alaska Natives. Available at: http://www.niddk.nih.gov/health/diabetes/pubs/amindian/amindian.htm. AccessedDate: June 28, 2001 Google Scholar ).

Using HbA(1c) to improve efficacy of the american diabetes association fasting plasma glucose criterion in screening for new type 2 diabetes in American Indians: the strong heart study.

To find an optimal critical line in the fasting plasma glucose (FPG)-HbA(1c) plane for identifying diabetes in participants with impaired fasting glucose (IFG) and thereby improve the efficacy of using FPG alone in diabetes screening among American Indians. We used FPG, 2-h postload glucose (2hPG), and HbA(1c) measured in the 2,389 American Indians (aged 45-74 years, without diabetes treatment or prior history of diabetes) in the Strong Heart Study (SHS) baseline (second) examination. Participants were classified as having diabetes if they had either FPG > or =126 mg/dl or 2hPG > or =200 mg/dl, as having IFG if they had 110 < or = FPG < 126 mg/dl, and as having normal fasting glucose (NFG) if they had FPG <110, according to the American Diabetes Association (ADA) definition. Logistic regression models were used for identifying diabetes (2hPG > or =200 mg/dl) in IFG participants. The areas under the receiver operating characteristic (ROC) curves generated by different logistic regression models were evaluated and compared to select the best model. A utility function based on the best model and the cost-to-benefit ratio was used to find the optimal critical line. The data from the second examination were used to study the effect of the time interval between the successive diabetes screenings on both the FPG criterion and the optimal critical line. A total of 37% of all subjects with new diabetes at baseline and 55.2% of those in the second exam had 2hPG > or =200 but FPG <126. There was a very large portion of IFG participants with diabetes (19.3 and 22.9% in the baseline and second exam, respectively). Among the areas under the ROC curves, the area generated by the logistic regression model on FPG plus HbA(1c) is the largest and is significantly larger than that based on FPG (P = 0.0008). For a cost-to-benefit ratio of 0.23888, the optimal critical line that has the highest utility is: 0.89 x HbA(1c) + 0.11 x FPG = 17.92. Those IFG participants whose FPG and HbA(1c) were above or on the line were referred to take an oral glucose tolerance test (OGTT) to diagnose diabetes. The optimal critical line is lower if a successive diabetes screening will be conducted 4 years after the previous screening. FPG > or =126 and 2hPG > or =200, as suggested by the ADA, are used independently to define diabetes. The FPG level is easy to obtain, and using FPG alone is suggested for diabetes screening. It is difficult to get physicians and patients to perform an OGTT to get a 2hPG level because of the many drawbacks of the OGTT, especially in those patients who already have FPG <126. It is also impractical to conduct an OGTT for everyone in a diabetes screening. Our data show that 37% of all subjects with new diabetes in the SHS baseline exam and 55.2% of those in the second exam have 2hPG > or =200 but FPG <126. These cases of diabetes cannot be detected if FPG is used alone in a diabetes screening. Therefore, although the small portion of diabetes in the NFG group (4.7% in the baseline and 6.9% in the second exam) may be ignored, those cases of diabetes among IFG participants ( approximately 20% in our data) need further consideration in a diabetes screening. It may be worthwhile for those IFG participants identified by the optimal critical line to take an OGTT. The optimal critical line and time interval between successive diabetes screenings need further study.

Incidence of diabetes in American Indians of three geographic areas: the Strong Heart Study.

To estimate incidence rates of diabetes and associated risk factors among participants of the Strong Heart Study. Of the 4,549 Strong Heart Study participants examined at baseline, 3,638 returned for a similar examination after an average of 4 years. The 1985 World Health Organization criteria for diabetes were used to identify new diabetes cases. Rates of diabetes among participants who did not have diabetes at baseline examination were determined. The relationships between the incidence rates of diabetes and a number of risk factors measured at baseline examination were studied. Significant variables associated with the development of diabetes included triglycerides, obesity, fasting plasma glucose, insulin, and degree of American Indian blood among participants with NGT at baseline. For those with IGT at baseline, significant predictors included fasting plasma glucose, 2-h glucose, BMI, degree of American Indian blood, and albuminuria. The high incidence rates found in this study were alarming. To slow down the rapid increase of this disease in the American Indian population, preventive programs must be designed and implemented. Patients with IGT should be treated with diabetes medication or put on a rigid weight-reduction program to reduce the risk of progression to diabetes.

Diabetes in American Indians and Alaska Natives

Diabetes in American Indians and Alaska Natives was the focus of a conference that resulted in a unique interchange among tribal leaders, health-care providers, and medical scientists with particular interests in diabetes mellitus and its complications. The conference, which was held in Mesa, Arizona, 14–17 November 1989, was sponsored by the Indian Health Service: and the National Institute of Diabetes and Digestive and Kidney Diseases, in collaboration with the Intertribal Council of Arizona.

Diabetes in American Indians: Reflections and future directions

The two goals of the next generation of diabetes research should be to reduce the incidence of diabetes mellitus and to decrease the risk of complications from the disease. The prevention of diabetes will require a better understanding of the interaction of genetic and host-environmental factors, especially energy balance, diet and exercise, and specific nutrients. The prevention of weight gain should probably be of highest priority. The prevention of complications needs to focus on hyperinsulinemia, hyperglycemia, blood pressure, smoking, and lipoproteins. Clinical trials are needed to evaluate objectively the benefits of specific interventions. Such trials should be closely linked to community health programs to maximize the health status of the population.

Diabetes in American Indians of Washington, Oregon, and Idaho.

The prevalence of diabetes among 29,000 American Indians living on or near 10 reservations in the Pacific Northwest was established from clinical data sources. The age- and sex-adjusted prevalence rate in 1987 was three times higher [95% confidence interval (CI) 2.8-3.1] than the comparable United States rate in 1980. The age-adjusted prevalence for women was 1.3 times that for men (95% CI 1.2-1.4). The prevalence varied by culture area. Reservation communities whose principal tribe came from the Great Basin culture area had 3.6 times more diabetes than found in the U.S. as a whole. Reservation communities whose principal tribe was from the Plateau culture had 3.0 times more diabetes than found in the U.S., and those from the Northwest Coast culture had 1.9 times more diabetes than found in the U.S. The reasons for these variations are unknown and warrant investigation.

Diabetes in American Indians: a growing problem.

Non-insulin-dependent diabetes mellitus is a major health problem in American Indian communities. Indian Health Service (IHS) collects information about outpatient visits and hospitalizations and analyzes mortality in American Indians and native Alaskans. Between October 1, 1982, and September 30, 1983 (fiscal year 1983), diabetes was the second leading clinical impression for all outpatient visits of patients 15 yr and older. Discharge diagnoses confirm both microvascular and macrovascular complications. Seventy-six percent of all IHS hospitalizations during fiscal year 1983 for lower-extremity amputation also coded diabetes. In 1982, the age-adjusted diabetes death rate per 100,000 was 19.9 for American Indians and native Alaskans, compared with 9.6 for all races in the United States.

Diabetes in American Indians and other native populations of the New World.

This is a review of previous and more recent observations on the prevalence and manifestations of diabetes in aboriginal populations of the New World. Rates of diabetes have now been measured or estimated in more than eighty of these groups in the Americas, Greenland, Polynesia, Micronesia and Melanesia. Diabetes was probably uncommon in all these native populations prior to 1940. It is now rife in many of these groups, but still rare in many. Among certain of these populations, rates of diabetes in adults still differ more than tenfold. Among groups of diabetics there are probably significant intertribal differences in the susceptibility to certain manifestations and complications such as retinopathy and coronary disease. There appear to be peculiarities in the insulin secretion patterns of certain of these tribes. The available evidence does not rule out the possibility that genetic factors play an important role in determining inter-tribal differences in prevalence and manifestations. But it is also clear that environmental factors exert powerful effects. Low rates of diabetes have been observed in Athapascan tribes and in some Shoshonean tribes. Diabetes was also rare prior to 1940 in Athapascan and Shoshonean Indians of Oklahoma. But diabetes has recently become common in these Oklahoma tribes. They were formerly lean and are now fat. The status of the many Oklahoma tribes is of particular interest because they represent seven of the eight major linguistic groups of North American Indians, having originated in very diverse parts of the Continent. Rates are now high in all Oklahoma tribes for which evidence is adequate to permit an estimate of prevalence. This includes fifteen tribes drawn from seven different linguistic groups. In seven additional Oklahoma tribes preliminary evidence, although less complete, suggests the probability that rates are also high. Studies of the dramatic emergence of diabetes and its manifestations in these aboriginal groups has considerable potential for gaining a better understanding of the genetic and environmental factors which influence risk and pathophysiology of diabetes and its complications.